In this year, we conducted three major sub-projects. First, we employed glucose and oxygen sensors coupled with high-speed amperometry to evaluate fluctuations in brain glucose and oxygen levels induced by oxycodone, an opioid analgesic drug frequently abused by humans. Second, we employed oxygen microsensors to examine fluctuations in brain oxygen levels induced by morphine at a wide range of doses, from low, analgesic to high that could result in adverse health effects. Third, we conducted a study, in which we examined oxygen and glucose responses induced by norephinephrine.